34 



The specimen is from the typical locality, in the Kinderhook 

 Group, at Le Giand, Iowa, and is in the collection of Wm. F. E. 

 Gurley. 



rOTERIOCEINUS MACCABEI, n. sp. 



Plate TIT, Fig. 3 , posterior side, natural size; Fig. If, same mag- 

 nified two diameters: Fig. o, azt/goits side of same .speci- 

 men magnified tiro diameters, part of the azijgoiis 

 area broken away, there is on this specimen a 

 Poteri'jcrinas dccrepitivs shoiring the 

 posterior side somewhat injured; 

 Fig, G, same, natural, size. 



Species small, bnt bearing very long rugged or geniculated 

 arms. Calyx obconoidal, as seen from the postei'ior side, but 

 quite unsymmetrical on account of the development of the azj^gous 

 area; height and greater diameter nearly equal; plates smooth. 

 Column small, round. 



Basals moderate size, in proportion to the calyx, with superior 

 angles acute. Subradials a little wider than high, except one on 

 the azygous side which has a length fully equal to the greater 

 width; four of them are hexagonal, the other two are heptagonal. 

 The azygous subradial, which is truncated at the top, is heptag- 

 onal and the largest plate in the calyx. The other heptagonal 

 plate is on the right of the azygous area and is a little largei- 

 than either of the hexagonal plates. First radials one-third wider 

 than high, quite convex longitudinally, which leaves the separat- 

 ing sutures much depressed, pentagonal and tiuucated the entire 

 width above, where the sutures are sliglitly gaping. A single, 

 long, rounded, brachial, supports upon the upper sloping sides, in 

 each radial series, the free arms. These brachials are contracted 

 in the middle part and of unequal lengtli ; the one opposite the 

 azygous area is the longer, the two adjacent are the shorter, and 

 the other two have an intermediate length. There are only ten 

 arms in this species; they are long and composed of rather long, 

 cuneiform, alternately projecting plates. Each projecting joint bears 

 a large, tapering, long jointed pinnule, which gives to the arms a 

 very rough or crisped aspect. 



The azygous area is wide and covered with a double series of 

 alternate plates. The first plate is pentagonal, longer than wide 

 and rests between the superior sloping sides of two subradials and 

 between the first radial on the right and the second azygous plate 

 on the left and is truncated on top for the third azygous plate; 



